Archer — On Apotheeia in Ai(j(P. 85 



XY. Os ArOTHECIA OCCITEEING TS some ScYTOIS'EMATOirS AJfD SlEOSI- 



PHOXACEOUS AlG^, IJf ADDIXIOIf TO THOSE PEEVIOTJSLY KXOWN. By 



WiXLiAii Archek, M. R. I. A. (With Plate 6.) 

 [Read December 14, 187-1:.] 



It is now some years since, upon examining some examples of the by 

 no means uncommon plant, long (and by some still) accepted as algal, 

 Stigonema atron'rens, Ag., that I was attracted by the peculiar en- 

 largements of the branches, and was much interested in perceiving that 

 this plant showed, imbedded in these swellings, distinctly lichenous 

 fructification — apotheeia, as well as the so-called spermogonia. Upon 

 searching out the literature of the subject, I found from Bomet's valu- 

 ahle paper*' that my discovery had been previously well known, and 

 that my specimens fully bore out the description he gave, with the 

 exception of the hyphse subsequently discovered by Schwendener. 

 Bomet, indeed, argued from the fructiiication which he had proved to 

 belong to this form, that it should no longer be accounted an alga, but 

 relegated to the lichens as E^ihehe pulescens. 



But it occurred to me that Bomet's supposition, at the period of 

 his writing the memoir on Ephebe, that other forms of apparent affi- 

 nity (^Stigonema mamillosum, St. inammiferum and others) were of 

 another and different nature — that is, "algse," whilst E. puhescens 

 was a "lichen," — could not be borne out. f It struck me, indeed, that 

 if Sfigo7iema atrovirens were no alga, but a veritable lichen, that then 

 the other Sirosiphonacem and Scytoneynacece, if likewise patiently ex- 

 amined, must prove themselves of the same nature. Stigonema mamil- 

 losum and Sii'osiphon- and Scytonema-fonns, I thought, could hardly 

 be less lichens than EpTxehe pubescens itself ; nor was I then aware that 

 such in some cases had, since Bomet's paper referred to, been actually 

 accepted as a fact. 



Having at that time more frequent opportunity of finding, amongst 

 the AYicklow lulls, the commoner representatives of the class than more 

 recently, I then made a considerable number of gatherings and ex- 

 amined them as closely as I could for " apotheeia." I found it a more 

 tedious labour than might be supposed, for, though I by and by found 

 apotheeia in three genera, I had to make very many hundred gather- 

 ings and examinations in order to be successful in encountering even 

 a few "fertile" specimens; for, though possibly more frequently 

 "fi'uiting" than one nught suppose from that fact, the opacity and 



* Bornet, " Recherches sur la Structure de V Ephebe pubescens," in " Ann. des 

 Sci. Naturelles," 3 ser., torn. xA'iii., p. 155. 

 t Bomet, loc. cit., p. 167. 



H. I. A. PROC, SER. II. VOL. IT.. SCIENCE. N 



